diff --git a/scst/include/scst.h b/scst/include/scst.h
index efe2bf5ec..23444523c 100644
--- a/scst/include/scst.h
+++ b/scst/include/scst.h
@@ -568,9 +568,6 @@ enum scst_exec_context {
 /* Set if tgt_dev has Unit Attention sense */
 #define SCST_TGT_DEV_UA_PENDING		0
 
-/* Set if tgt_dev is RESERVED by another session */
-#define SCST_TGT_DEV_RESERVED		1
-
 /*************************************************************
  ** I/O grouping types. Changing them don't forget to change
  ** the corresponding *_STR values in scst_const.h!
@@ -2355,14 +2352,14 @@ struct scst_dev_registrant {
 struct scst_device {
 	unsigned int type;	/* SCSI type of the device */
 
+	/* Set if reserved via the SPC-2 SCSI RESERVE command. */
+	struct scst_session *reserved_by;
+
 	/*************************************************************
 	 ** Dev's flags. Updates serialized by dev_lock or suspended
 	 ** activity
 	 *************************************************************/
 
-	/* Set if dev is RESERVED */
-	unsigned int dev_reserved:1;
-
 	/* Set if double reset UA is possible */
 	unsigned int dev_double_ua_possible:1;
 
diff --git a/scst/src/scst_lib.c b/scst/src/scst_lib.c
index a8f3efdde..d6bb3b093 100644
--- a/scst/src/scst_lib.c
+++ b/scst/src/scst_lib.c
@@ -4197,8 +4197,6 @@ static int scst_alloc_add_tgt_dev(struct scst_session *sess,
 
 	spin_lock_bh(&dev->dev_lock);
 	list_add_tail(&tgt_dev->dev_tgt_dev_list_entry, &dev->dev_tgt_dev_list);
-	if (dev->dev_reserved)
-		__set_bit(SCST_TGT_DEV_RESERVED, &tgt_dev->tgt_dev_flags);
 	spin_unlock_bh(&dev->dev_lock);
 
 	head = &sess->sess_tgt_dev_list[SESS_TGT_DEV_LIST_HASH_FN(tgt_dev->lun)];
@@ -5057,16 +5055,9 @@ static void scst_clear_reservation(struct scst_tgt_dev *tgt_dev)
 	TRACE_ENTRY();
 
 	spin_lock_bh(&dev->dev_lock);
-	if (dev->dev_reserved &&
-	    !test_bit(SCST_TGT_DEV_RESERVED, &tgt_dev->tgt_dev_flags)) {
+	if (scst_is_reservation_holder(dev, tgt_dev->sess)) {
 		/* This is one who holds the reservation */
-		struct scst_tgt_dev *tgt_dev_tmp;
-		list_for_each_entry(tgt_dev_tmp, &dev->dev_tgt_dev_list,
-				    dev_tgt_dev_list_entry) {
-			clear_bit(SCST_TGT_DEV_RESERVED,
-				    &tgt_dev_tmp->tgt_dev_flags);
-		}
-		dev->dev_reserved = 0;
+		scst_clear_dev_reservation(dev);
 		release = 1;
 	}
 	spin_unlock_bh(&dev->dev_lock);
@@ -7668,22 +7659,12 @@ void scst_process_reset(struct scst_device *dev,
 	TRACE_ENTRY();
 
 	/* Clear RESERVE'ation, if necessary */
-	if (dev->dev_reserved) {
-		list_for_each_entry(tgt_dev, &dev->dev_tgt_dev_list,
-				    dev_tgt_dev_list_entry) {
-			TRACE_MGMT_DBG("Clearing RESERVE'ation for "
-				"tgt_dev LUN %lld",
-				(long long unsigned int)tgt_dev->lun);
-			clear_bit(SCST_TGT_DEV_RESERVED,
-				  &tgt_dev->tgt_dev_flags);
-		}
-		dev->dev_reserved = 0;
-		/*
-		 * There is no need to send RELEASE, since the device is going
-		 * to be reset. Actually, since we can be in RESET TM
-		 * function, it might be dangerous.
-		 */
-	}
+	scst_clear_dev_reservation(dev);
+	/*
+	 * There is no need to send RELEASE, since the device is going
+	 * to be reset. Actually, since we can be in RESET TM
+	 * function, it might be dangerous.
+	 */
 
 	dev->dev_double_ua_possible = 1;
 
@@ -8657,10 +8638,8 @@ void scst_reassign_retained_sess_states(struct scst_session *new_sess,
 
 		/** Reassign regular reservations **/
 
-		if (dev->dev_reserved &&
-		    !test_bit(SCST_TGT_DEV_RESERVED, &old_tgt_dev->tgt_dev_flags)) {
-			clear_bit(SCST_TGT_DEV_RESERVED, &new_tgt_dev->tgt_dev_flags);
-			set_bit(SCST_TGT_DEV_RESERVED, &old_tgt_dev->tgt_dev_flags);
+		if (scst_is_reservation_holder(dev, old_sess)) {
+			scst_reserve_dev(dev, new_sess);
 			TRACE_DBG("Reservation reassigned from old_tgt_dev %p "
 				"to new_tgt_dev %p", old_tgt_dev, new_tgt_dev);
 		}
diff --git a/scst/src/scst_priv.h b/scst/src/scst_priv.h
index 325d92cd8..4b03e6725 100644
--- a/scst/src/scst_priv.h
+++ b/scst/src/scst_priv.h
@@ -564,6 +564,54 @@ void scst_acn_sysfs_del(struct scst_acn *acn);
 
 #endif /* CONFIG_SCST_PROC */
 
+/*
+ * Check SPC-2 reservation state.
+ * Must not be called from atomic context.
+ */
+static inline bool scst_dev_reserved(struct scst_device *dev)
+{
+	return dev->reserved_by;
+}
+
+/*
+ * Whether @sess holds a reservation on @dev.
+ * The caller may but does not have to hold dev->dev_lock.
+ */
+static inline bool scst_is_reservation_holder(struct scst_device *dev,
+					      struct scst_session *sess)
+{
+	EXTRACHECKS_BUG_ON(sess == NULL);
+	return dev->reserved_by == sess;
+}
+
+/*
+ * Whether another session than @sess holds a reservation on @dev.
+ * The caller may but does not have to hold dev->dev_lock.
+ */
+static inline bool scst_is_not_reservation_holder(struct scst_device *dev,
+						  struct scst_session *sess)
+{
+	struct scst_session *reserved_by = dev->reserved_by;
+
+	EXTRACHECKS_BUG_ON(sess == NULL);
+	return reserved_by != NULL && reserved_by != sess;
+}
+
+static inline void scst_reserve_dev(struct scst_device *dev,
+				    struct scst_session *sess)
+{
+	EXTRACHECKS_BUG_ON(sess == NULL);
+	dev->reserved_by = sess;
+}
+
+static inline void scst_clear_dev_reservation(struct scst_device *dev)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 32)
+	lockdep_assert_held(&dev->dev_lock);
+#endif
+	dev->reserved_by = NULL;
+}
+
 void scst_tgt_dev_del_free_UA(struct scst_tgt_dev *tgt_dev,
 			      struct scst_tgt_dev_UA *ua);
 void scst_dev_check_set_UA(struct scst_device *dev,
diff --git a/scst/src/scst_targ.c b/scst/src/scst_targ.c
index 8c447e256..046d0f039 100644
--- a/scst/src/scst_targ.c
+++ b/scst/src/scst_targ.c
@@ -2037,7 +2037,6 @@ static int scst_reserve_local(struct scst_cmd *cmd)
 {
 	int res = SCST_EXEC_NOT_COMPLETED;
 	struct scst_device *dev;
-	struct scst_tgt_dev *tgt_dev_tmp;
 
 	TRACE_ENTRY();
 
@@ -2079,21 +2078,12 @@ static int scst_reserve_local(struct scst_cmd *cmd)
 	}
 
 	spin_lock_bh(&dev->dev_lock);
-
-	if (test_bit(SCST_TGT_DEV_RESERVED, &cmd->tgt_dev->tgt_dev_flags)) {
+	if (scst_is_not_reservation_holder(dev, cmd->sess)) {
 		spin_unlock_bh(&dev->dev_lock);
 		scst_set_cmd_error_status(cmd, SAM_STAT_RESERVATION_CONFLICT);
 		goto out_done;
 	}
-
-	list_for_each_entry(tgt_dev_tmp, &dev->dev_tgt_dev_list,
-			    dev_tgt_dev_list_entry) {
-		if (cmd->tgt_dev != tgt_dev_tmp)
-			set_bit(SCST_TGT_DEV_RESERVED,
-				&tgt_dev_tmp->tgt_dev_flags);
-	}
-	dev->dev_reserved = 1;
-
+	scst_reserve_dev(dev, cmd->sess);
 	spin_unlock_bh(&dev->dev_lock);
 
 out:
@@ -2113,7 +2103,6 @@ out_done:
 static int scst_release_local(struct scst_cmd *cmd)
 {
 	int res = SCST_EXEC_NOT_COMPLETED;
-	struct scst_tgt_dev *tgt_dev_tmp;
 	struct scst_device *dev;
 
 	TRACE_ENTRY();
@@ -2142,7 +2131,12 @@ static int scst_release_local(struct scst_cmd *cmd)
 	 * is closed (see scst_free_tgt_dev()), but this actually doesn't
 	 * matter, so use lock and no retest for DEV_RESERVED bits again
 	 */
-	if (test_bit(SCST_TGT_DEV_RESERVED, &cmd->tgt_dev->tgt_dev_flags)) {
+	if (scst_is_not_reservation_holder(dev, cmd->sess)) {
+		/*
+		 * SPC-2 requires to report SCSI status GOOD if a RELEASE
+		 * command fails because a reservation is held by another
+		 * session.
+		 */
 		res = SCST_EXEC_COMPLETED;
 		cmd->status = 0;
 		cmd->msg_status = 0;
@@ -2150,13 +2144,7 @@ static int scst_release_local(struct scst_cmd *cmd)
 		cmd->driver_status = 0;
 		cmd->completed = 1;
 	} else {
-		list_for_each_entry(tgt_dev_tmp,
-				    &dev->dev_tgt_dev_list,
-				    dev_tgt_dev_list_entry) {
-			clear_bit(SCST_TGT_DEV_RESERVED,
-				&tgt_dev_tmp->tgt_dev_flags);
-		}
-		dev->dev_reserved = 0;
+		scst_clear_dev_reservation(dev);
 	}
 
 	spin_unlock_bh(&dev->dev_lock);
@@ -2205,7 +2193,7 @@ static int scst_persistent_reserve_in_local(struct scst_cmd *cmd)
 		goto out_done;
 	}
 
-	if (dev->dev_reserved) {
+	if (scst_dev_reserved(dev)) {
 		TRACE_PR("PR command rejected, because device %s holds regular "
 			"reservation", dev->virt_name);
 		scst_set_cmd_error_status(cmd, SAM_STAT_RESERVATION_CONFLICT);
@@ -2309,7 +2297,7 @@ static int scst_persistent_reserve_out_local(struct scst_cmd *cmd)
 	TRACE(TRACE_SCSI, "PR action %x for '%s' (LUN %llx) from '%s'", action,
 	    dev->virt_name, tgt_dev->lun, session->initiator_name);
 
-	if (dev->dev_reserved) {
+	if (scst_dev_reserved(dev)) {
 		TRACE_PR("PR command rejected, because device %s holds regular "
 			"reservation", dev->virt_name);
 		scst_set_cmd_error_status(cmd, SAM_STAT_RESERVATION_CONFLICT);
@@ -2464,8 +2452,7 @@ int __scst_check_local_events(struct scst_cmd *cmd, bool preempt_tests_only)
 		cmd->double_ua_possible = 1;
 
 	/* Reserve check before Unit Attention */
-	if (unlikely(test_bit(SCST_TGT_DEV_RESERVED,
-			      &tgt_dev->tgt_dev_flags))) {
+	if (unlikely(scst_is_not_reservation_holder(dev, tgt_dev->sess))) {
 		if ((cmd->op_flags & SCST_REG_RESERVE_ALLOWED) == 0) {
 			scst_set_cmd_error_status(cmd,
 				SAM_STAT_RESERVATION_CONFLICT);
@@ -3308,11 +3295,9 @@ static int scst_pre_dev_done(struct scst_cmd *cmd)
 			cmd, cmd->status);
 
 		if ((cmd->cdb[0] == RESERVE) || (cmd->cdb[0] == RESERVE_10)) {
-			if (!test_bit(SCST_TGT_DEV_RESERVED,
-					&cmd->tgt_dev->tgt_dev_flags)) {
-				struct scst_tgt_dev *tgt_dev_tmp;
-				struct scst_device *dev = cmd->dev;
+			struct scst_device *dev = cmd->dev;
 
+			if (scst_is_reservation_holder(dev, cmd->sess)) {
 				TRACE(TRACE_SCSI, "RESERVE failed lun=%lld, "
 					"status=%x",
 					(long long unsigned int)cmd->lun,
@@ -3320,15 +3305,8 @@ static int scst_pre_dev_done(struct scst_cmd *cmd)
 				PRINT_BUFF_FLAG(TRACE_SCSI, "Sense", cmd->sense,
 					cmd->sense_valid_len);
 
-				/* Clearing the reservation */
 				spin_lock_bh(&dev->dev_lock);
-				list_for_each_entry(tgt_dev_tmp,
-						    &dev->dev_tgt_dev_list,
-						    dev_tgt_dev_list_entry) {
-					clear_bit(SCST_TGT_DEV_RESERVED,
-						&tgt_dev_tmp->tgt_dev_flags);
-				}
-				dev->dev_reserved = 0;
+				scst_clear_dev_reservation(dev);
 				spin_unlock_bh(&dev->dev_lock);
 			}
 		}